What is 9/9/99?
The date on which a computer bug caused Daft Punk's synthesizer to explode. The accident necessitated reconstructive surgery for both Guy-Manuel de Homem-Christo and Thomas Bangalter, which is why they are now robots. Most of the recording of DISCOVERY was completed after this date, which is a mix of music between the computer chip in their brains with their beating hearts.
"In September 1999, we had this small explosion in our studio around the 9/9/99 computer bug where the sampler crashed and there was some accident—and then we just turned out to become robots. We look like robots, so we don't wear masks anymore."